Show selection indicator in talk list.

Small fliebeltje on the right of the view is visible for highlighted views. The ListFragment keeps track of which view is currently selected because apparently the default "setSelected" method does not apply for list items.
Make sure the talk location label is single line.

Messes up the list item layout when is very little room.
Fixed crash on orientation change.

The main activity got confused when the details fragment used to be visible but is no longer accesible when the screen orientation changed. Fixed by introducing LayoutUtils helper.
Store highlight status in talk model instead of view.

Storing it in the view causes issues with reusing list item views.
Increased master-detail width selector to w720dp.

The original w600dp is too narrow for the very long titles of some of these talks.
Decreased extra margins width selector to w600dp.

The original w820dp was too restrictive: these wall-of-text abstracts need all the help they can get.